1. Field of the Invention
The present invention relates to an articulated robot equipped with an arm.
2. Description of the Related Art
An articulated robot changes its position and posture by changing the angle at a joint arranged between the arms thereof. A wrist is arranged at the tip of the arm and a work tool such as a hand is attached to the wrist. A lot of work tools are provided with a driving mechanism which necessitates the supply of electric power or air etc. Further, there are cases where electric signals are transmitted to the work tool in order to drive the same. The electric power, air and electric signals etc., are provided to the work tool by electric wiring or piping referred to as wire bodies.
The wire bodies connected to the work tool are connected to the robot to supply electric power etc. The robot is equipped with a connection member at which the wire body is connected. A connector and a tube coupling correspond to the connection member. It is preferable for such the connection member to be positioned near the work tool so as to facilitate the connection of the wire bodies. Accordingly, the connection member is generally equipped on the surface of the arm of the robot near the work tool.
Japanese Unexamined Patent Publication No. 2013-212560 discloses a robot comprising a connection part which includes connecting main body, a hollow connector housing, and a support member which supports terminals. It is disclosed that the connection part protrudes from the surface of the arm, and the pull-out direction of the connector which is connected to the connection part are set to be a predetermined direction of a rotation axis.
The articulated robot is often arranged in an environment which is crowded with other robots or peripheral devices. Accordingly, it is desirable that the area of interference when the robot moves be small. However, the connection member such as the connectors or tube couplings protrudes from the surface of the arm. Accordingly, there is a problem that the connection member may easily interfere with surrounding devices such as other robots, or portions of the robot other than the connection member.
Further, for articulated robots used in factories for producing food, pharmaceuticals, and etc., it is necessary to maintain a high level of cleanliness in view of hygiene. A worker can maintain the cleanliness by cleaning the robot with a chemical solution or water. However, the connection member of the prior art protrudes from the surface of the arm, resulting in the problem that it is easy for foreign substances such as dirt or cleaning liquid to accumulate around the connection member. Thus, the level of cleanliness may deteriorate or more effort may be required for cleaning.
In particular, robots which is used in an environment where liquid such as cleaning liquid is splashed have a configuration to seal the inside of the arm to prevent the entry of liquid therein. A packing is arranged between the surface of the arm and the connection member. However, the packing is gradually eroded by foreign substances which accumulate at the bottom of the connection member. As a result, there is a problem that it is easier for foreign substances to enter the inside of the arm from sealed portions between the connection member and the arm than sealed portions other than the connection member.